Allow for mounting as an engine
Allow for mounting as an engine

Sort URL generation should be irrespective of the app/engine url_helpers to allow for mounting as an engine- #url_to replaced with #resource_path

fixes #5, fixes #8, fixes #13

bolshakov/activeadmin_sortable_table,mvdstam/activeadmin-sortable,jcgertig/activeadmin-orderable,brightbytes/activeadmin-orderable,brightbytes/activeadmin-orderable,jcgertig/activeadmin-orderable,mvdstam/activeadmin-sortable,bolshakov/activeadmin_sortable_table,bolshakov/activeadmin_sortable_table